Photovoltaic cell and process for producing the same

Abstract

A dye-sensitized photovoltaic cell comprising an electroconductive support, a porous photovoltaic layer constituted with a porous semiconductor layer containing a photosensitizing dye, a hole transporting layer, and a support on a counter electrode side, the porous photovoltaic layer having a multi-layer structure, and the semiconductor layer having a haze ratio at a wavelength in a visible light region of 60% or more.

What is claimed is:  
     
       1. A dye-sensitized photovoltaic cell comprising: 
       an electroconductive support,  
       a porous photovoltaic layer comprising a porous semiconductor layer containing a photosensitizing dye,  
       a hole transporting layer,  
       a counter electrode, and  
       wherein the porous photovoltaic layer comprises a multi-layer structure, and the semiconductor layer of the porous photovoltaic layer has a haze ratio at a wavelength in a visible light region of 60% or more.  
     
     
       2. A dye-sensitized photovoltaic cell as claimed in  claim 1 , wherein semiconductors of respective layers of the porous photovoltaic layer have a multi-layer structure and have different particle diameters. 
     
     
       3. A dye-sensitized photovoltaic cell as claimed in  claim 1 , wherein the porous photovoltaic layer having a multi-layer structure comprises particles having different particle diameters that are sequentially increased from a light receiving surface. 
     
     
       4. A dye-sensitized photovoltaic cell as claimed in  claim 1 , wherein in the porous photovoltaic layer having a multi-layer structure, the porous photovoltaic layer on a side of a light receiving surface has a uniform particle diameter. 
     
     
       5. A dye-sensitized photovoltaic cell as claimed in  claim 1 , wherein the porous photovoltaic layer having a multi-layer structure comprises layers arranged in an order, from a light receiving surface, from a layer having a maximum sensitivity wavelength region on a short wavelength side in the absorption spectrum to a layer having a maximum sensitivity wavelength region on a long wavelength side in the absorption spectrum. 
     
     
       6. A dye-sensitized photovoltaic cell comprising: 
       an electroconductive support,  
       a porous photovoltaic layer comprising a porous semiconductor layer containing a photosensitizing dye, the porous photovoltaic layer having a multi-layer structure,  
       a hole transporting layer,  
       a support on a counter electrode side, and  
       wherein semiconductors of respective layers of the porous photovoltaic layer having a multi-layer structure have different particle diameters.  
     
     
       7. A dye-sensitized photovoltaic cell as claimed in  claim 6 , wherein the porous photovoltaic layer having a multi-layer structure comprises particles having different particle diameters that are sequentially increased from a light receiving surface. 
     
     
       8. A dye-sensitized photovoltaic cell as claimed in  claim 6 , wherein in the porous photovoltaic layer having a multi-layer structure, the porous photovoltaic layer on a side of a light receiving surface has a uniform particle diameter. 
     
     
       9. A dye-sensitized photovoltaic cell as claimed in  claim 6 , wherein the porous photovoltaic layer having a multi-layer structure comprises layers arranged in an order, from a light receiving surface, from a layer having a maximum sensitivity wavelength region on a short wavelength side in the absorption spectrum to a layer having a maximum sensitivity wavelength region on a long wavelength side in the absorption spectrum. 
     
     
       10. A process for producing a dye-sensitized photovoltaic cell comprising an electroconductive support, a porous photovoltaic layer having a multi-layer structure containing a photosensitizing dye provided on the electroconductive support, an electroconductive layer, and a support on a counter electrode side, a second and subsequent photovoltaic layers from a light receiving surface being formed at a temperature of 200° C. or less. 
     
     
       11. A process for producing a dye-sensitized photovoltaic cell as claimed in  claim 10 , wherein the second and subsequent photovoltaic layers are formed by an electrodeposition method. 
     
     
       12. A process for producing a dye-sensitized photovoltaic cell as claimed in  claim 11 , wherein a porous photovoltaic layer having a water soluble dye adsorbed on a surface thereof is formed by the electrodeposition method using a metallic inorganic salt solution containing the water soluble dye. 
     
     
       13. A process for producing a dye-sensitized photovoltaic cell as claimed in  claim 11 , wherein an electrolytic potential in the electrodeposition method is in a range of from −0.7 to −1.3 V (vs. SCE). 
     
     
       14. A process for producing a dye-sensitized photovoltaic cell as claimed in  claim 11 , wherein the electrodeposition method is carried out at a temperature in a range of from 0 to 100° C. 
     
     
       15. A process for producing a solar cell comprising a dye-sensitized photovoltaic cell comprising an electroconductive support, a porous photovoltaic layer having a multi-layer structure formed on the electroconductive support, an electroconductive layer, and a support on a counter electrode side, wherein the photovoltaic layer comprises at least one porous semiconductor layer and a dye, the process comprising: 
       the photovoltaic layer being produced by adsorbing a dye on particles and a film of the porous semiconductor layer, wherein the film of the porous semiconductor layer is provided at least partially over the particles of the porous semiconductor layer,  
       removing the film of the porous semiconductor layer including the dye adsorbed thereon, and  
       adsorbing another dye.  
     
     
       16. A process for producing a solar cell comprising a dye-sensitized photovoltaic cell comprising an electroconductive support, a porous photovoltaic layer having a multi-layer structure including at least one porous semiconductor layer and comprising a dye, and an electroconductive layer, the process comprising: 
       the photovoltaic layer being produced by adsorbing a dye on particles and a film of the porous semiconductor layer, wherein the film of the porous semiconductor layer is provided at least partially over the particles of the porous semiconductor layer,  
       removing the film of the porous semiconductor layer including the dye adsorbed thereon, and  
       adsorbing another dye.  
     
     
       17. A dye-sensitized photovoltaic cell comprising at least the following components in the following order: 
       an electroconductive support;  
       a porous photovoltaic layer having a two-layer structure and comprising a photosensitizing dye, wherein the two layers of the porous photovoltaic layer each comprise a semiconductor and a dye;  
       a carrier transport layer; and  
       a support on a counter electrode side.